Might and Magic Book One: The Secret of the Inner Sanctum (also known as Might and Magic Book 1, Might and Magic 1, MM1 or simply Might and Magic) is an early role-playing video game, first in the popular and influential Might and Magic franchise. It was released in 1986 as New World Computing's debut, ported to numerous platforms and re-released continuously through the early '90s.
The game is set on the world of VARN which features expansive outdoor terrain, castles, caves, underground cities and an Astral Plane.
The game centers on six adventurers who are trying to discover the secret of the Inner Sanctum: a kind of 'holy grail' quest. While trying to discover the Inner Sanctum, the heroes discover information about a mysterious character named Corak and his hunt for the missing villain Sheltem. They end up unmasking Sheltem, who had been masquerading as the King, and defeating his evil machinations. At the end of the game they go through the 'Gates to Another World' and travel to CRON, not knowing that Sheltem has also escaped to that world.
Although it appears to take place in a straightforward medieval fantasy setting of knights in armor, mythical monsters and magicians, a number of science fiction elements are revealed later in the game, down to the actual meaning of VARN (Vehicular Astropod Research Nacelle). This was a relatively common trait of early CRPGs, as also seen in the oldest Ultima and Wizardry titles. For example, the Sheltem plot is first introduced when the adventurers visit the site of a crashed space ship and are told by aliens that their prisoner is at large in the world.
The characters in Might and Magic and its successors are defined by a number of rules, conforming loosely to the fantasy role-playing archetypes. Characters have 'statistics' (analogous to Dungeons and Dragons Ability scores) of Might, Endurance, Accuracy, Personality, Intelligence and Luck.
There are six character classes:

Knight characters are based on the Dungeons and Dragons Fighter class.

Cleric characters are like D&D Clerics.

Robbers are like the old D&D Thief class.

Sorcerers (called Wizards in the NES version) are like the old Magic-Users.

Paladins are fighter type characters who gain access to Clerical magic at higher experience levels. Unlike their D&D equivalent, there is no restriction on their alignment.

Archers are more limited fighter characters, who can use ranged weapons even when on the front line of combat, and gain access to Sorcerer spells at higher levels.

The player assigns each character a race at creation time: Human, Elf, Half-orc, Gnome or Dwarf. This affects the character's starting statistics, and their resistance to various forms of attack.
Alignment is also chosen for all characters, but because the party acts collectively all of the time, the implications of this are minimal. Alignment plays some part in the game, in particular to determine the reward for one of the game's quests.
Characters can also be male or female. Like alignment, gender serves minimal purpose in the game, save for a few situations (notably, the city of Portsmith, in which all males, and only males, are injured when stepping through certain areas of the city). A character's gender can be changed back and forth via certain actions within the game world.